- http://stnsoft.com/DVD/index.html (previous version: http://dvd.sourceforge.net/dvdinfo/)
Structure of the DVD
The file system is UDF (Universal Disk Format ?) There are two kinds of files: VM (Video Manager) in files VIDEO_xxx and VTS (video track sets) in files VTS_xxx. The data parts are in .IFO files, and .BUP is a backup. The video files are in .VOB files. On commercial DVDs, .VOB files are usually encrypted with dvdCSS (Content Scrambling Code), while .IFO files are in clear.
The .IFO embed simple sequences of code called PGC (ProGram Chain). When a DVD is inserted in the player, the player first starts to play a particular PGC, the FP_PGC (First Play PGC).